engineering practices lab (group b) manual

7/31/2019 Engineering Practices lab (Group B) Manual

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Basic Circuit Symbols

SYMBOL NAME

Resistor

Variable Resistor

Capacitor

Variable Capacitor

Inductor

Diode

DC Voltage

AC Voltage

Battery or Power Supply

Wire

Cross WireNo Connection

Cross WireConnection

Ground

Transformer

SPST Switch

SPDT Switch

DPDT Switch

Fuse

AND Gate


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NAND Gate

OR Gate

NOR Gate

XOR Gate

NOT Gate

Lamp

Voltmeter

Ammeter

Milliammeter

Motor

Generator

Open Switch

Closed Switch

Open Push Switch

Closed Push Switch


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ELECTRICAL ENGINEERING PRACTICE

List of Experiments:

1. Residential house wiring using switches, fuse, indicator, lamp and energy-meter.2. Fluorescent lamp wiring.3. Stair case wiring.4. Measurement of electrical quantitiesvoltage, current, power & power factor in RLC

circuit.

5. Measurement of energy using single phase energy meter.6. Measurement of resistance to earth of an electrical equipment


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Safety Rules and Regulations:

Turn off power and unplug from wall before working on electric or electronic circuits,except when absolutely necessary.

Do not work on electrical equipment in a wet area or when touching an object that mayprovide a hazardous earth ground path.

Remove metal jewelry, watches, rings etc before working on electrical circuits. Never overload circuits. Never place containers of liquids on electrical systems. Safely discharge capacitors in equipment before working on the circuits. Make sure that the last connection to be made in the circuit is be the power supply and

the first thing to be disconnected is also the power supply.

Never make any changes to circuits without first isolating the circuit by switching off andremoving connections to the power supplies.

Use extension cords only when necessary and on a temporary basis. Keep soldering irons in their protective stand when not in use. Always observe polarity when connecting components into a circuit. Turn off the power sources after completing the experiment. In case of damage of any component or device, report to the faculty in charge

immediately.


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Wiring Layout:

Residential House Wiring Using Switches, Fuse, Indicator, Lamp and Energy-meter


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Expt.No:1

RESIDENTIAL HOUSE WIRING USING SWITCHES, FUSE, INDICATOR, LAMP

AND ENERGYMETER.

Aim:

To construct residential house wiring using switches, indicator, fuse, lamp and energy-

meter.

Materials Required:

S.No Items Range Quantity

1 Energy Meter 10A, 250V 1

2 Porcelain fuse 16A 2

3 Main box 10A, DPST 1

4 Distribution box 3way 1

5 Copper wires 1mm2 lamp2.5mm2 power

Asrequired

6 Single pole switch 6A , 230V 1

7 3-pin socket 6A 1

8 Indicator - 1

9 Lamp holder - 1

10 Round block - 2

11 Wooden board - 2

12 PVC Pipe-

As reqd

13 Wooden screw - As reqd

14 Screw driver - 115 Cutting plier - 1

16 Tester - 1

17 Knife - 1

Procedure:

1. Mark the location of electrical items on the given wooden board.2. Mark lines for wiring on the board.3. Fix PVC pipes of required lengths along the lines with the help of clips.4. Connect wires through the pipes5. Fix the bulb holder and switches in their corresponding locations.6. Fix the bulb and make connections as per the wiring diagram.7. Switch on the main and check if the bulb glows.

Result:

A household wiring was thus prepared and tested.


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Wiring Layout:

Fluorescent Lamp Wiring

Starter

1, 230V, 50Hz AC Supply


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Expt.No:2

FLUORESCENT LAMP WIRING

Aim:

To assemble and check the accessories of a fluorescent lamp.

Materials Required:


1 1/18 PVC copper wire - As reqd

2 1-pole flush type switch 6A, 250V 1

3 Fluorescent lamp 40W 1

4 Copper choke 40W 1

5 Starter 1


7 Screw driver - 18 Cutting pliers - 1

9 Tester - 1

10 Knife - 1

Working Principle:

Fluorescent lamp is a low pressure mercury lamp and is a long evacuated tube. It contains

a small amount of mercury and argon gas at 2.5mm pressure. At each end of the tube there is a

tungsten electrode which is coated with fast electron emitting material. The inside of the tube is

coated with phosphor according to the type of light. A starter helps to start the tube and break the

circuit. The electrodes in the starter cause discharge in argon gas after consequent heating. The

bimetallic strip then bends and causes the contacts in the starter to close. Hence, the choke,

filaments in the tube ends and the starter are in series. When current flows through the filaments,

heat is produced. This causes the contacts in the starter to move apart which results in a sudden

break in the circuit causing a high value of emf to be induced in the choke. According to Lenzs

law, the direction of the induced emf in the choke will try to oppose the fall of current in the

circuit. The voltage across the tube ends will be high enough to cause a discharge in the gas

inside the tube making it glow.

Procedure:

1. Fix the choke and lamp holders in the tube fitting.2. Make connections as per the circuit diagram3. Switch on the power supply and check if the lamp glows.


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Result:

The accessories of fluorescent lamp are assembled and the circuit is checked.


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Wiring Layout:

Staircase Wiring

Observation:

Switch 1 Switch 2 Lamp

ON ON

ON OFF

OFF ONOFF OFF


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Expt.No:3

STAIR-CASE WIRING

Aim:

To prepare a staircase wiring in which one lamp is controlled by two switches.

Materials Required:


1 3-way junction box - 1

2 2-pole flush type switch 5A, 250V 2

3 Incandescent lamp 40W 1

4 PVC pattern lamp holder - 1

5 Clamps As reqd


7 Screw driver - 18 Cutting pliers - 1

9 Tester - 1

10 Knife - 1

11 Wooden screws As reqd

12 PVC pipe - As reqd

13 Copper wire - As reqd

Principle:

In staircase wiring, a lamp is controlled from two different places. If a lamp is switched

on in one location it can be switched off using a switch in another location and vice-versa. Two

2-way switches are used for the purpose. Supply is given to one switch at the short-circuited

terminal. The connection to the lamp is taken from a similar short-circuited terminal of the

second switch. Other two independent terminals of each switch are connected by cables.

Procedure:

1. Draw lines on the wooden board using chalk where wiring has to be made.2. Fix the PVC pipes on the wooden board using clamps.3. Make connections as per the circuit diagram.4. Connect the lamp holder and fix the lamp in the lamp holder.5. Switch on the supply and check if the bulb glows.

Result:

Thus a staircase wiring for the bulb was prepared and tested.


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Wiring Layout:

Measurement of electrical quantities Voltage, Current, Power & Power Factor in RLC

circuit

Observation:

Multiplication Factor =

S.NoVoltage

V (V)

Current

I (A)

Wattmeter

Reading (W)Actual

Power

(W)

Power

Factor

Observed Actual


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Expt.No:4

MEASUREMENT OF ELECTRICAL QUANTITIES VOLTAGE, CURRENT, POWER

& POWER FACTOR IN RLC CIRCUIT

Aim:

To measure electrical quantities voltage, current, power and power factor in a RLC

circuit.

Materials Required:


1 Voltmeter (0-300)V, MI 1

2 Ammeter (0-10)A, MI 1

3 Wattmeter 300V, 10A, LPF 1

4 RLC load 5kW 1

5 Auto-transformer 230V/ (0-270)V 1

6 Connecting Wires As reqd

Principle:

Power in an electric circuit can be measured using a wattmeter. A wattmeter consists of

two coils namely current and pressure or potential coil. The current coil measures quantity that is

proportional to the current in the circuit and the pressure coil measures quantity that is

proportional to voltage in the circuit. The given wattmeter is loaded by direct loading. The

ammeter is connected in series to the wattmeter. Since the same current flows through both the

coils, the current and voltage across the circuit are constant.

Procedure:

1. Make connections as per the wiring layout.2. No load is applied initially.3. Set the auto-transformer to minimum voltage before switching on the power supply.4. With no load applied, set the rated voltage in the auto-transformer and note down the

ammeter, voltmeter, wattmeter readings and multiplication factor of the wattmeter.

5. Adjust the RLC load and tabulate the ammeter, voltmeter and wattmeter readings.6. Repeat the procedure till ammeter reads 10A.7. Gradually reduce the load and voltage in the auto-transformer to a minimum and switchon the power supply.8. Calculate the indicated power and power factor.

Calculation:

Actual Power = Pw * Multiplication factor


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where Pw Observed wattmeter reading

Apparent Power = V*Iwhere V - Voltmeter reading

I - Ammeter reading

Power factor, cos = Actual Power / Apparent Power

Result:

Thus the values of voltage, current, power and power factor of a RLC circuit are

measured.


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Wiring Layout:

Measurement of energy using single phase energy-meter

Observation:

Multiplication factor =

S.No

Supply

voltage V

(V)

Load Current

I (A)

Wattmeter

reading P

(W)

Time t

(s)

True Energy

Pt/3600*1000

(kWh)

Measured

Energy

n/750(kWh)


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Expt.No:5

MEASUREMENT OF ENERGY USING SINGLE PHASE ENERGY METER

Aim:

To measure the energy in a single phase circuit using energy meter.

Materials Required:


1 Single phase Energy meter 750 rev/kWh,

240V, 50Hz

1

2 Wattmeter 300V, 10A 1

3 Ammeter 10A, MI 1

4 Voltmeter 300V, MI 1

5 Stop watch - 1

6 Load Resistive,5kW

1

7 Connecting Wires - As reqd

Principle:

An electric meter or energy meter is a device that measures the amount of electrical

energy supplied to or produced by a residence, business or machine.

The most common type is a kilowatt hour meter. Modern electricity meters operate by

continuously measuring the instantaneous voltage (V) and current (A) and finding the product of

these to give instantaneous electrical power (W) which is then integrated against time to give

energy used (kWh).

Procedure:

1. Make connections as per the wiring layout.2. Switch on the supply, adjust the voltage and switch on the load3. Note down the time taken for one revolution in the energy meter and tabulate the

corresponding ammeter and voltmeter readings

4. Repeat the above procedure for different load currents.5. Release the load gradually and switch off the supply.

Calculation:

Energy meter specification = 750 revolutions / kWh

True Energy = Power P (W) * time t (s)= P * t / 3600 * 1000 kWh


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Measured Energy = n / 750 kWhwhere nno. of revolutions / sec

Result:

Thus energy of a single phase circuit is measured using an energy meter.


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Wiring Layout:

Observation:

S.No Earth Resistance (M)

Average Value :


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Expt.No:6

MEASUREMENT OF RESISTANCE TO EARTH OF ELECTRICAL EQUIPMENT

Aim:

To measure the earth resistance or insulation resistance of the given electrical equipment

(transformer).

Materials Required:


1 Transformer 0-230V/110V 1

2 Megger - 1

3 DPST switch - 1

Principle:

A megger or a mega-ohmmeter is used to test the insulation resistance or resistance toearth of electrical equipments. The name is derived from the fact that the insulating resistance of

a properly designed appliance is of the order of tens or hundreds of mega-ohms. The measured

resistance is intended to indicate the condition of the insulation or dielectric between two

conductive parts, where the higher the resistance, the better the condition of the insulation.

Ideally, the insulation resistance would be infinite, but as no insulators are perfect, leakage

currents through the dielectric will ensure that a finite (though high) resistance value is

measured.

Procedure:

1. Make connections as per the wiring layout.2. The DPST switch is kept open.3. Supply desired voltage to the megger for its operation.4. Tabulate the megger reading.5. Repeat the procedure 5-6 times and calculate the average value. The average value gives

the earth resistance of the transformer.

Result:

The earth resistance of the given transformer is found using a megger.


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ELECTRONICS ENGINEERING PRACTICE

List of Experiments:

1. Study of Electronic components and equipmentsResistor color coding, measurement of AC signalparameters (peak-peak, rms period, frequency) using CRO.2. Study of logic gates AND, OR, EOR and NOT.

3. Generation of Clock Signal.4. Soldering practiceComponents, devices and circuitsUsing general purpose PCB.5. Measurement of ripple factor of half wave rectifier (HWR) and full wave rectifier (FWR).


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Resistor Color Coding:

Cathode Ray Oscilloscope(CRO):

Front Panel of CRO:


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Expt.No:1

STUDY OF ELECTRONIC COMPONENTS AND EQUIPMENTSRESISTOR COLOR

CODING, MEASUREMENT OF AC SIGNAL PARAMETERS (PEAK-PEAK, RMS PERIOD,

FREQUENCY) USING CRO

Aim:

To study the basic electronic components and equipments.

Materials Required:

Resistors Cathode Ray Oscilloscope Mulitmeter

Theory:

Resistors:

Color coding in resistors indicates the values or ratings of resistors. It is also used in

capacitors and inductors. The advantage of color coding is that essential information can be

marked on small components of cylindrical shape without the need to print all the

specifications. Resistor values are always coded in ohms.

Band A - first significant digit of component value

Band B - second significant digit

Band C - decimal multiplier

Band D - (if present) tolerance value in percentageFor example, a resistor with bands ofyellow, violet, red and gold will have first digit

4(yellow), second digit 7(violet), followed by 2(red) zeros: 4,700 ohms. Gold signifies that

the tolerance is 5%.

Actual resistor value = 4700 5% .

Cathode Ray Oscilloscope:

Oscilloscope is a type ofelectronic test instrument that allows observation of constantly

varying signal voltages, usually as a two-dimensional graph of one or more electrical potential

differences using the vertical or 'Y' axis, plotted as a function of time (horizontal or 'x' axis).Many signals, for example sound, can be converted to voltages and displayed this way. Signals

are often periodic and repeat constantly, so that multiple samples of a signal which is actually

varying with time are displayed as a steady picture. Many oscilloscopes (storage oscilloscopes)

can also capture non-repeating waveforms for a specified time, and show a steady display of the

captured segment.
http://en.wikipedia.org/wiki/Electronic_test_instrumenthttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Potential_differencehttp://en.wikipedia.org/wiki/Potential_differencehttp://en.wikipedia.org/wiki/Potential_differencehttp://en.wikipedia.org/wiki/Potential_differencehttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Electronic_test_instrument


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Observation:

Resistor Color Coding:

S.No

Resistor Value

Using Color Code Using Multimeter

Measurement of AC signal parameters using CRO:

S.No

Input Signal

Frequency

(Hz)

Output Signal

Vp-p

(V)

Vmax

(V)

Vrms

(V)

Time

(s)

Frequency

(Hz)


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Oscilloscopes are commonly used to observe the exact wave shape of an electrical signal.

This allows the measurement of, for example, peak-to-peak voltage of a waveform, the

frequency of periodic signals, the time between pulses, the time taken for a signal to rise to full

amplitude (rise time), and relative timing of several related signals.

Oscilloscopes are used in the sciences, medicine, engineering, and telecommunications

industry.

Working Principle:

The device consists mainly of a vacuum tube which contains a cathode, anode, grid,

X&Y-plates, and a fluorescent screen.

When the cathode is heated by applying a small potential difference across its terminals,

it emits electrons. Having a potential difference between the cathode and the anode (electrodes),

accelerate the emitted electrons towards the anode, forming an electron beam, which passes to

fall on the screen. When the fast electron beam strikes the fluorescent screen, a bright visible

spot is produced. The grid, which is situated between the electrodes, controls the amount of

electrons passing through it thereby controlling the intensity of the electron beam. The X&Y-

plates are responsible for deflecting the electron beam horizontally and vertically. A sweep

generator is connected to the X-plates, which moves the bright spot horizontally across the

screen and repeats that at a certain frequency as the source of the signal. The voltage to be

studied is applied to the Y-plates. The combined sweep and Y-voltages produce a graph showing

the variation of voltage with time.

Procedure:

1. Connect the output of a function generator to CH1 of the CRO.2. Select sine wave input of any frequency in the function generator.3. Tabulate the peak-to-peak voltage and time readings.4. Repeat the procedure for different input frequencies and tabulate them.

Calculation:

Peak-to-peak voltage Vpp = No. of vertical divisions X Volt/Division RMS voltage Vrms =

Time t = No. of horizontal divisions X Time/Division Frequency f = 1/t
http://en.wikipedia.org/wiki/Waveformhttp://en.wikipedia.org/wiki/Rise_timehttp://en.wikipedia.org/wiki/Rise_timehttp://en.wikipedia.org/wiki/Waveform


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Capacitor Coding:

Diode:


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Capacitors:

A capacitor (originally known as condenser) is a passive two-terminal electricalcomponent used to store energy in an electric field. The forms of practical capacitors vary

widely, but all contain at least two electrical conductors separated by a dielectric (insulator).

Capacitors are widely used in electronic circuits for blocking direct current while allowingalternating current to pass, in filter networks, for smoothing the output ofpower supplies, in the

resonant circuits that tune radios to particular frequencies, in electric power transmission systemsfor stabilizing voltage and power flow, and for many other purposes.

Diodes:

A diode is a two terminal semiconductor device which allows an electric current to pass

in one direction (called the diode's forward direction), while blocking current in the opposite

direction (the reverse direction). This unidirectional behavior is called rectification, and is used

to convert alternating current to direct current.

Multimeter:

A multimeter or a multi-tester, also known as a VOM (Volt-Ohm meter), is an electronic

measuring instrument that combines several measurement functions in one unit. A typical

multimeter may include features such as the ability to measure voltage, current and resistance.

Multimeters may use analog or digital circuitsanalog multimeters (AMM) and digital

multimeters (DMM or DVOM.) Analog instruments are usually based on a micro-ammeter

whose pointer moves over a scale calibrated for all the different measurements that can be made;

digital instruments usually display digits.

Bread board:

A breadboard is used to make up temporary circuits for testing or to try out an idea. No

soldering is required so it is easy to change connections and replace components. Parts will not

be damaged so they will be available to re-use afterwards. Breadboards have many tiny sockets

(called 'holes') arranged on a 0.1" grid. The leads of most components can be pushed straight into

the holes. ICs are inserted across the central gap with their notch or dot to the left. The top and

bottom rows are linked horizontally all the way across. The other holes are linked vertically in

blocks of 5 with no link across the centre.
http://en.wikipedia.org/wiki/Passivity_(engineering)http://en.wikipedia.org/wiki/Terminal_(electronics)http://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Dielectrichttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Power_supplyhttp://en.wikipedia.org/wiki/LC_circuithttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Rectification_(electricity)http://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Measuring_instrumenthttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Analog_circuithttp://en.wikipedia.org/wiki/Digital_circuithttp://en.wikipedia.org/wiki/Microammeterhttp://en.wikipedia.org/wiki/Microammeterhttp://en.wikipedia.org/wiki/Digital_circuithttp://en.wikipedia.org/wiki/Analog_circuithttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Measuring_instrumenthttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Rectification_(electricity)http://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/LC_circuithttp://en.wikipedia.org/wiki/Power_supplyhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Dielectrichttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Terminal_(electronics)http://en.wikipedia.org/wiki/Passivity_(engineering)


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Digital Multimeter Symbols:

Bread board:


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Result:

Thus resistor color coding, measurement of AC signal parameters (peak-peak, rms period, frequency)

using CRO and multimeter are studied.


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AND Gate:

Pin Configuration

C = A.B

Logic Symbol

OR Gate:

Pin Configuration

C = A + B

Logic Symbol


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Expt.No:2

STUDY OF LOGIC GATES AND, OR, EOR AND NOT

Aim:

To study the principles of logic gates AND, OR, XOR and NOT.Materials Required:


1 AND gate IC 7408 1

2 OR gate IC 7432 1

3 XOR gate IC 7486 1

4 NAND gate IC 7400 1

5 NOR gate IC 7402 1

6 NOT gate IC 7404 1

7 Digital IC trainer kit - 18 Connecting Wires - As reqd

Theory:

A logic gate performs a logical operation on one or more logic inputs and produces a single

logic output. Logic gates are primarily implemented using diodes or transistors acting as

electronic switches. Logic circuits include such devices as multiplexers, registers, arithmetic

logic units (ALUs), and computer memory, all the way up through complete microprocessors,

which may contain more than 100 million gates.

AND Gate:

A HIGH output (1) results only if both the inputs to the AND gate are HIGH (1). If anyone of the inputs is LOW (0), a LOW (0) output results. The AND gate with inputs A and B and

output C implements the logic expression C= A.B

Truth Table:

Input Output

C = A.BA B

0 0 0

0 1 0

1 0 0

1 1 1

OR Gate:

A HIGH output (1) results if one or both the inputs to the gate are HIGH (1). If neither

input is HIGH, a LOW output (0) results. The OR gate with inputs A and B and output C

implements the logic expression C= A+B
http://en.wikipedia.org/wiki/Logical_operationhttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Switch#Electronic_switcheshttp://en.wikipedia.org/wiki/Multiplexerhttp://en.wikipedia.org/wiki/Processor_registerhttp://en.wikipedia.org/wiki/Arithmetic_logic_unithttp://en.wikipedia.org/wiki/Arithmetic_logic_unithttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Microprocessorhttp://en.wikipedia.org/wiki/Microprocessorhttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Arithmetic_logic_unithttp://en.wikipedia.org/wiki/Arithmetic_logic_unithttp://en.wikipedia.org/wiki/Processor_registerhttp://en.wikipedia.org/wiki/Multiplexerhttp://en.wikipedia.org/wiki/Switch#Electronic_switcheshttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Logical_operation


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NOT Gate:

Pin Configuration

Logic Symbol C = A'

XOR Gate:

Pin Configuration

Logic Symbol C = A XOR B


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Truth Table:

Input Output

C = A+BA B

0 0 0

0 1 11 0 1

1 1 1

XOR Gate:

The XOR gate (sometimes EOR gate, or EXOR gate) is a digital logic gate that

implements an exclusive or; that is, a true output (1) results if one, and only one, of the inputs to

the gate is true (1). If both the inputs are false (0) or both are true (1), a false output (0) results. It

represents the inequality function, i.e., the output is HIGH (1) if the inputs are not alike

otherwise the output is LOW (0). The XOR gate with inputsA andB implements the logical

expression .

Truth Table:

Input Output

C = A XOR BA B

0 0 0

0 1 1

1 0 1

1 1 0

NOT Gate:

An inverter or NOT gate is a logic gate which implements logical negation. An inverter

circuit outputs a voltage representing the opposite logic-level to its input. An inverter with input

A implements the logical expression A = A'

Truth Table:

Input

A

Output

A = A'

0 1

1 0

NAND Gate:

A NAND gate (Negated AND or NOT AND) is a logic gate which produces an output

that is false only if all its inputs are true. A LOW (0) output results only if both the inputs to the

gate are HIGH (1); if one or both inputs are LOW (0), a HIGH (1) output results.
http://en.wikipedia.org/wiki/Logic_gatehttp://en.wikipedia.org/wiki/Exclusive_orhttp://en.wikipedia.org/wiki/Logic_gatehttp://en.wikipedia.org/wiki/Logical_negationhttp://en.wikipedia.org/wiki/Logic_gatehttp://en.wikipedia.org/wiki/Logic_gatehttp://en.wikipedia.org/wiki/Logical_negationhttp://en.wikipedia.org/wiki/Logic_gatehttp://en.wikipedia.org/wiki/Exclusive_orhttp://en.wikipedia.org/wiki/Logic_gate


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NAND Gate:

Pin Configuration

Logic Symbol C = (A.B) '

NOR Gate:

Pin Configuration:

Logic Symbol C = (A + B) '


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Truth Table:

Input Output

C = (A.B)'A B

0 0 1

0 1 1

1 0 11 1 0

NOR Gate:

A HIGH output (1) results if both the inputs to the gate are LOW (0); if one or both input

is HIGH (1), a LOW output (0) results. NOR is the result of the negation of the OR operator.

Truth Table:

Input Output

C = (A+B)'A B

0 0 10 1 0

1 0 0

1 1 0

Procedure:

1. Make connections as per the pin diagram.2. Give the required supply and ground connections to the ICs.3. Inputs are applied using switches and outputs through LEDs.

Result:

Thus the logic gates are studied and their truth tables are verified.
http://en.wikipedia.org/wiki/Negationhttp://en.wikipedia.org/wiki/Logical_disjunctionhttp://en.wikipedia.org/wiki/Logical_disjunctionhttp://en.wikipedia.org/wiki/Negation


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Pin Configuration of IC 555

Circuit Diagram


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Expt.No:3

GENERATION OF CLOCK SIGNAL

Aim:

To construct a circuit that generates an automatic clock signal.

Materials Required:


1 Timer IC IC 555 1

2 Resistors 10K 2

3 Capacitors 0.01F0.1F

11

4 Diode 1N4001 1

5 RPS 0-30V 1

6 CRO - 17 Probes - 2


Theory:

555 is a very commonly used IC for generating accurate timing pulses. An astablemultivibrator is generally used for the purpose of generating pulses. In such a circuit, both the

high and low levels of output produced by the multivibrator are unstable. The output thus keeps

vibrating between both the levels and hence a pulse wave is generated. The IC 555 can be

configured very easily to work as an astable multivibrator. The time during which the output iseither high or low is determined by two resistors and a capacitor, which are connected externally

to the 555 timer.

Procedure:1. Connections are made as per the circuit diagram.2. A supply of +5V is given through pin8 of the IC.3. A square wave output is observed at pin3 using a CRO.4. The on-time and off-time of the observed waveform are tabulated.5. The frequency of the wave is then calculated using the formula f= 1/T.

Formula Used:

Time T = TON + TOFF (s) Frequency f = 1/T (Hz)

Result:Thus a clock pulse was generated using IC555.

Observed Frequency =


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Expt.No:4

SOLDERING PRACTICECOMPONENTS, DEVICES AND CIRCUITSUSING

GENERALPURPOSE PCB

Aim:

To solder electronic components using a PCB and check their continuity.

Materials Required:


1 Soldering Iron 1

2 Solder 1

3 Printed Circuit Board 1

Theory:

Soldering is the process of joining thin metal plates or wires made of steel, copper or

brass. It is very commonly used to join wires in electrical work and mount electroniccomponents on a circuit board. The joining material used in soldering is called as solder or

filler rod. An alloy of tin and lead is commonly used as the solder. The flux is used to clean the

surface of the plates/wires to be soldered. Aluminum chloride or zinc chloride is commonly

used as flux. A good soldering iron is a variable temperature setting type with interchangeable

irons and tips. The tip should be removed regularly to prevent oxidation scale from accumulating

between the heating element and the tip.

Soldering Simple Electronic Components:

A printed circuit board (PCB) consists of copper strips and pads bonded to a

plastic board. The copper strip is the network of interconnecting conductive path. Leads of

components mounted on the board are inserted through holes on the board and the conductive

copper. These leads are soldered to the copper at the end of the hole. If excessive heat is

applied to copper, it may get lifted from the board or the components on the board get

damaged. Soldering pencil gun of about 30 Watts is used to heat the junction. The

surface of copper bonded to the board should be properly prepared and cleaned before

soldering. Flux is applied on circuits and component leads.

Check the conductive strips and pads on the board before soldering. Avoid excess

solder to prevent two copper paths from bridging. When solder globules form on the junction

area, remove them by cleaning the soldering tip using a cloth.

Checking Continuity:

The continuity of a wire conductor without a break has practically zero ohms of

resistance. Therefore, an ohmmeter may be used to test continuity. To test continuity,

select the lowest ohm range. A wire may have an internal break, which is not visible due to

insulation, or the wire may have a bad connection at the terminals. Checking for zero ohms


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between any two points tests the continuity. A break in the conducting path is evident

from the reading of infinite resistance.

In a cable of wires, individual wires are identified with colors. Consider the

figure, where the individual wires are not seen, but you wish to find the wire that

connects to terminal A. This is done by, checking continuity of each wire to terminal A. The

wire that has zero ohms is the one connected to this terminal. Continuity of a long cable may

be tested by temporarily short-circuiting the other ends of the wires. The continuity of both

wires may be checked for zero ohms.

In a digital multimeter, a beep mode is available to check continuity. The connectivity

between the terminals is identified by the beep sound.

Procedure:1. The surface to be soldered is cleaned and flux applied.2. The soldering iron is heated to the required temperature.3. The soldering iron melts the solder rod and a thin film of solder spreads over the

surface to join the plates/wires.

4. Continuity of the components are then checked.

Result:

The components are soldered and their continuity is checked.


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Circuit Diagram:

Half Wave Rectifier

Without filter:

With Filter:

Model Graph:


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Expt.No:5

MEASUREMENT OF RIPPLE FACTOR OF HALF WAVE RECTIFIER AND FULL

WAVE RECTIFIER

Aim:

To construct a half wave and full wave rectifier circuit and calculate the ripple factor.

Materials Required:


1 Transformer 230V / 6-0-6V, 200mA

1

2 Diode IN4007 2

3 Resistor 1K 1

4 CRO - 1

5 Bread Board - 1


Theory:

A rectifier converts alternating current (AC) to direct current (DC). The simplest kind of

rectifier circuit is half wave rectifier circuit. It allows only half of the AC waveform to passthrough the load. The primary of the transformer is connected to ac supply. This induces an ac

voltage across the secondary of the transformer. During the positive half cycle of the input

voltage the polarity of the voltage across the secondary forward biases the diode. As a result a

current IL flows through the load resistor, RL. The forward biased diode offers a very lowresistance and hence the voltage drop across it is very small. Thus the voltage appearing across

the load is practically the same as the input voltage at every instant.

A Full Wave Rectifier is a circuit, which converts an ac voltage into a pulsating dcvoltage using both half cycles of the applied ac voltage. It uses two diodes of which one conducts

during one half cycle while the other conducts during the other half cycle of the applied acvoltage. During the positive half cycle of the input voltage, diode D1 becomes forward biased

and D2 becomes reverse biased. Hence D1 conducts and D2 remains OFF. The load current

flows through D1 and the voltage drop across RL will be equal to the input voltage. During thenegative half cycle of the input voltage, diode D1 becomes reverse biased and D2 becomes

forward biased. Hence D1 remains OFF and D2 conducts. The load current flows through D2

and the voltage drop across RL will be equal to the input voltage.

Procedure:

1. Connections are made as per the circuit diagram.2. The output waveform is observed using a CRO.3. The ripple factor is calculated using the voltage of the observed waveform.


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Full Wave Rectifier

Without Filter:

With Filter:

Model Graph:


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Formula Used:

Half Wave Rectifier

Ripple Factor = (

) where Vrms =

Vdc =

Full Wave Rectifier

Ripple Factor = ( )

where Vrms =

Vdc =

Result:

Thus a half wave rectifier and full wave rectifier circuits are constructed and their ripple

factors are calculated.

Ripple factor of HWR =

engineering practices lab (group b) manual

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